Material handling mechanism for lift trucks



J. G. LORD 2,782,065

MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS Feb. 19, 1957' v 8 Sheets-Sheet 1 Filed July 8, 1955 INVENTOR. Jami G. LORD BY FIG.

Feb. 19, 1957 J. G. LORD 2,782,065

MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS Filed July 8, 1955 v I 8 Sheets-Shee t 2 4 v I26 I20 42 so 92\ g I 34- W q 22 k J g GT) 26 Q -20 I INVENTOR. Jon-m G. Loan FIG. 2 fW Feb. 19, 1957 J. G. LORD MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS Filed July 8, 1955 s. Shee'ts-Shet s INVENTOR.

J'orm G. I Lo no Feb. 19, 1957 J. G. LORD ,065

MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS Filed July 8, 1955 8 Sheets-Sheet 4 FIG.4

\. N I p N no q- C (0 q (9 IO U Q N' v Q INVENTOR. N Jorm G. L

Feb. 19, 1957 Filed July 8, 1955 J. G. LORD 2,782,065

MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS 8 Sheets-Sheet 5 INVENTOR. Jonu G. Leno Feb. 19, 195

Filed July 8, 1955 7 J. cs. LORD MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS 8 Sheets-Sheet 6 FlG. 6

' FIG. ;s

. INVENTOR. JOHN G. LORD BY Feb. 19, 1957 J. G. LORD 2,782,065

MATERIAL HANDLING MECHANISM FOR LIFT TRUCKS Filed July 8, 1955 INVENTOR. Jen-m Loan kn/iW 8 Sheets-Sheet 8 MATERIAL HANDLBNG MEfIHANEll/l FDR LET TRUCKS John G. Lord, Swarthmore, Pan, assignor, by mesne asslgnments, to Shell Development (3a., a corporation Application na s, 1955, semi No. 524mm 4 Claims. or. 294--8i) This invention relates to improvements in lift trucks, and more particularly, to an improved material-handling and load-gripping mechanism for power-operated lift trucks, and to lift trucks utilizing such mechanism.

Jaw-clamping lift trucks have been widely used for handling and moving a large variety of materials and objects 'in industrial plants, warehouses, loading plat-' forms, and the like. Such lift trucks are normally provided withloa'd-gripping jaws which move in unison towards and away from the central portion of the jawcarrying carriage to effect gripping of the load at the vertical center portion of the carriage.

Such prior lift trucks are less versatile and useful than they otherwise might be, particularly, for loading materials and objects into narrow storage spaces, or into a corner or adjacent a stack of stored material, because of the inability of the truck to carry the load at one side.

Prior lift trucks,lift clamps and load gripping mechanisms have also suffered the serious disability of being limited in respect to the minimum size package which may be handled by the jaws. culty is the fact that the hydraulic cylinder or cylinders which actuates the jaws interferes with or obstructs the joining-together movement of the jaws.

Moreover, in a number of constructions, it has proven necessary to provide centrally-positioned bumpers or guard plates which interfere with the closing of the jaws on small objects.

An object of the present invention is the provision of a load handling mechanism in which controlled and regulated sidewise shifting of the load may be accomplished.

A further object of the present invention is the provision of a load handling mechanism in which the use of pallets is dispensed with.

A still further object of the present invention is the provision of a load handling mechanism in which both small objects, and large objects having a width exceeding that of the truck carriage may be readily and securely grasped and lifted.

A still further object of the present invention is the provision of a load handling mechanism which will overcome the shortcomings of prior devices.

Another object of the present invention is the provision of a superior lift truck construction.

Still further objects will appear hereinafter.

For the purpose of illustrating the invention, there is shown in the accompanying drawings one form thereof which is at present preferred, although it is to be under stood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangements and organizations of the instrumentalities as herein shown and described.

Referring to the drawings, like reference characters refer to like parts:

Figure 1 is a perspective view of one embodiment of the lift truck of the present invention with the material handling device of the present invention installed thereon.

Figure 2 is a plan view of the lift truck shown in Figure 1 looking down from above, with the transverse One cause of this difii- United States Fatent Tl i 2,782,065 Patented F eb. 19, .1957

2 cross-member of the lift frame removed to permit better observation of the parts.

Figure 3 is a fragmentary perspective view of the front portion of the lift truck of Figure 1.

Figure 4 is a fragmentary perspective view similar to that of Figure 3 but with the load-grasping jaws removed, in order to better reveal the parts.

Figure 5 is a fragmentary perspective view of the front portion of Figure l with the jaws displaced to one side.

Figure 6 is a horizontal sectional view of the load handling mechanism with parts removed for better observation.

Figure 7 is an enlarged view of the circled area designated 7 on Figure 6.

Figure 8 is an enlarged view of the circled area designated 8 on Figure 6.

Figure 9 is a vertical section of a portion of the load handling mechanism taken along the line 9-9 of Figure 4.

Figure 10 is a fragmentary horizontal section of one side of the load handling mechanism.

such as a three-wheeled truck can be used.

' Inasmuch as the load is handled in front of the front wheels, the trucks engine 3b is preferably positioned at the rear of the truck, in order to act as a counterweight. If necessary, or desirable, an additional counterweight may be added to supplement the weight of the engine. I

A mast designated generally as 32, which, in the main, is made of known construction, comprises a pair of C- shaped channels 34 disposed in spaced-apart verticallyextending parallel relationship. The upper ends of C shaped channels 34 are joined together by means of a generally C-shaped backwardly-extending bracket 36.

A lift frame 38 comprising a pair of vertical channelshaped members 42 joined by atop-most horizontal transverse cross-member 4%, moves reciprocably vertically within C-shaped channels 34. The lift frame 38 may be actuated by various means, such as by a vertical hydraulic cylinder 44 having a piston rod 46 extending upwardly into engagement with transverse cross-member 4t), whereby lift frame 33 may be raised or lowered in response to the movement of the piston rod 46. A hydraulic pump or engine and lever-operated control valves (not shown) may be used to operate the vertical hydraulic cylinder 44 and thus raise or lower lift frame 38.

A load-lifting carriage designated generally as 43 is secured to lift frame 38, as shown particularly in Figure 2.

Load-lifting carriage 48 comprises a back plate 50 having a smooth planar front surface 52 (see Figure '9) onto which an upper way or guide 54 and a lower way or guide 56 are fixedly secured by mounting guide tracks 58, 60 and 62 thereon. Thus, uppermost guide track 58 and lowermost guide track 62 each comprise a pair of inwardly extending identical bearing members 64, an intervening spacer bearing member 66 which retains bearing members 64 at a predetermined and parallel spaced distance from each other, and a frontrnost clamp plate 68 which is coextensive with bearing members 64. A threaded bolt 70 passes through clamp plate 68, bearing members 64 and spacer bearing member 66 into back plate 50, anchoring the guide tracks 58 and 62 to back.

plate 50. The front face of a clamp plate 68 is countersunk to provide a nest for the head of bolt 70.

Centrally positioned guide track 60 resembles guide tracks 58 and 62, except that bearing members 640 extend beyond spacer bearing member 66a an equal distance in both directions, and clamp plate 68a is enlarged to compensate for the extra size of bearing members 640. Bearing members 64a are maintained at the same spaced distance from each other by spacer member 66a and are the same thickness as the bearing members 64 of guide tracks 58 and 62.

Primary sliders 72 and 74 ride within respective guides 54 and 56. Thus, primary slider 72 comprises a pair of feet 76 and 78. Foot 76 of leg 77 of primary slider 72 rides between bearing members 64 of guide track 58, and foot 73 of leg 79 of primary slider 72 rides between the upper portion of the bearing members 64a of guide track 60. Foot 30 of leg 81 of primary slider 74 rides between the lower portion of bearing members 64a of guide track 60, and foot 82 of leg 83 of primary slider 74 rides between bearing members 64 of guide track 62.

The legs 77 and 79 of primary slider 72 are joined at their inner end by thrust plate 84 which extends frontwardly for a shorter distance than legs 77 and 79. Similarly, legs 81 and 33 of primary slider 74 are joined together at their inner end by a thrust plate 86.

Actuating cylinders 88 and 90 are disposed respectively in guides 54 and 56 and are straddled by primary sliders 72 and 74, respectively. Actuating cylinder 88 is anchored to back plate 50 by means of anchor plate 92 and cylinder 90 is anchored to back plate 50 by means of anchor plate 94. Piston rod )6 from cylinder 88 is bolted to thrust plate 84 of primary slider 72 and piston rod 98 of cylinder 90 is bolted to thrust plate 86 of primary slider 74.

The front portions of each of primary sliders 72 and 74 are provided with respective inwardlyextending flanges 100 and 102 which together with the legs of sliders 72 and 74 serve as guides or ways for secondary sliders .104 and 106.

Secondary sliders 104 and 106 are generally U-shaped in cross-section, with the base of the U frontward and extending frontward a suflicient distance from back plate 50 to clear cylinders 88 and 90, and anchor plates 92 and 94 (see in particular Figures 9).

The coupling of the secondary sliders to their associated primary sliders and to the back plate is described below for secondary slider 106 and primary slider 74 (see in particular, Figures 6 through 9).

The upper surface of primary slider 74 "is provided with a boss 108 adjacent the end of primary slider 74 carrying thrust plate 86. A sprocket gear wheel 110 is mounted on boss 108. A similar boss carries sprocket gear wheel 112 adjacent the other end of primary slider 74. A chain 114 passes over both sprocket gear wheels 110 and 1.12, with one link 116 of the rear span of chain 114 anchored to clamp plate 68a of guide track 60, which as heretofore noted, is fixedly anchored onto back plate A second and oppositelypositioned link 1153 on the front span of chain 114 is anchored to secondary slider 166. Identical chain and sprocket means on the underside of secondary slider 104 (not fully shown) are used to connect secondary slider 104 to primary slider 72 and to clamp plate 68:: of guide track 60.

The front surface 105 of secondary slider 104 comprises an irregularly-shaped polygon having its maximum width at its outside end portion, and its minimum width, which corresponds; to the span width of secondary slider 134, at its inner end portion. Similarly, front surface 107 of secondary slider 106 has its maximum width at itsoutcr end portion and its minimum width at its inner end portion, the extensions in the region of maximum width of both the front surfaces 105 and 107 being centrally directed (see Figure 4).

The central portion of each of the front surfaces and 107 are provided with respective jaw-anchoring flanges 120 and 122 whichv cooperate with the enlarged outer end portions of front surfaces 105 and 107 to provide an anchorage for the jaws. Each of flanges 120 and 12?. comprise a generally L-shaped member with the base of the L being frontwardly disposed and directed outwardly, and with top of the L integral with the front surface 105 or 107. Flanges 120 and 122 are identical in height, extending generally from a point on the plane leg 77 of primary slider 72 to a point on the plane of leg 83 of primary slider 74.

Jaws 124 and 126 are mounted respectively on secondary sliders 104 and 106. Thus, a series of threaded bolts 130 (five bolts for each jaw in the embodiment shown in the drawings) are inserted through the back flange 128 of jaw 124 and are threaded into threaded openings 131 in the wide portion of the front surface 105 of secondary slider 104, as seen most clearly in Figure 9. The front face of back flange 128 is countersunk or drilled as shown in Figure 9 in order to provide a recess in which the heads of the bolts 130 may be nested. The inner end of back flange 128 is rabbeted with jaw anchoring flange 120.

Jaw 126 is secured to secondary slider 106 through its back flange 132 by means of bolts 134 and rabbeting with jaw anchoring flange 122, in an identical fashion as heretofore described for the joining of jaw 124 to secondary slider 104.

Jaws 124 and 126 are each provided with a pair of jaw pads 136 and 133, which may comprise metal plates retained by metal clips to the forwardly extending prong flanges 142 of the jaws 124 and 126. Each of jaws 124 and 126 is further provided with a pair of prong flange sets, one for each of the jaw pads, each set comprising a group of three flanges 142a, 1142b, and 1426 (see in particular, Figure 3). Prong flanges 142a and 1420 are long flanges extending almost the full length of the jaw pads, whereas central prong flange 142b extends forwardly for but a fraction of the length of flanges 142a and 142a; flange 1421: being secured by a retaining block and screw 140.

Each of the jaw pads 136 and 138 is spaced slightly from the adjacent surfaces of the prongs so that any load gripping pressure on the center portion of the jaw pads will exert itself primarily against center prong flange 142b and relatively slightly against the outer ends of prong flanges 142a and 142a; while pressure on the innermost ends of the pads will cause the pad to fulcrum about the center prong flange 14212 and will tend to pull the two longer prongs 142a and 142a inwardly slightly. The pads are thus provided with a degree of flexibility permitting the accommodation of packages whose dimensions are note quite uniform in a fore-and-aft direction or in an up-and-down direction. Jaw pads 136 and 138 are surfaces with a plastic layer 137, which may be Plastasol made by Goodyear Tire & Rubber Co.

The operation of the present invention is as follows:

Truck 20 is maneuvered towards the'object to be lifted. If the object is in an exposed position, then jaws 124 and 126 may be spread open a distance somewhat greater than the width of the object, with each jaw being more or less equidistant from the vertical center line of back plate 50 (see the positions assumed by the jaws in Figures 1, 2 and 3). The opening of the jaws 124 and 126 is accomplished by applying fluid under pressure to cylinders 88 and 90 and retracting respective piston rods 96 and 98.

The retraction of piston rods 96 and 98 moves primary sliders 72 and 74 away from each other. Secondary sliders 1M and 106 move away from each other at twice the rate of primary sliders 72 and 74 due to the arrangement of the chain and sprocket heretofore described.

Thus, in the case of secondary slider 106, link 116 of chain 114 being fixedly secured in respect to back plate 50 effects a doubling in the extent of movement of secondary slider 106 in relation to the rate of movement of primary slider 74. Similarly, the chain and sprocket arrangement for primary slider 72 and secondary slider 104 will likewise effect a two-fold multiplication in the relative movement of secondary slider 104. Inasmuch as jaws 124 and 126 are joined to secondary sliders 104 and 106, the jaws 124 and 126 will be moved apart at double the speed of primary sliders 72 and 7 4.

With the jaws so-spread, truck 20 is advanced so that jaws 124 and 126 straddle the object to be moved, at which time the jaws are brought together so as to clamp ingly embrace the object. This is accomplished by extending the piston rods 96 and 98.

Jaws 124 and 126 move together at twice the relative rate of primary sliders 72 and 74 due to the heretoforeexplained chain and sprocket arrangement. When the object is securely clamped, pressure is retained on piston rods 96 and 98 and the object can be raised by raising piston rod 46 from cylinder 44, which in turn raises lift frame 38 which carries carriage 48. Of course, while the object is being raised and moved, positive pressure is at all times applied to jaws 124 and 126 to maintain a secure clamping action on the object.

Where it is desired to move an object being carried to one end of carriage 48 (as shown in Figure this can be accomplished by applying pressure through one of the actuating cylinders 88 or 90 and not through the other, or by applying pressure in the opposite direction in the other cylinder. Thus, as shown in Figure 5 piston rod 98 is extended. Since no pressure (or, if desired, oppositelydirected pressure) is applied to piston rod 96 it will be retracted as jaw 126 will move jaw 124 outwardly by engagement therewith, either directly, as shown in Figure 5 or through the medium of the object being handled. Thi will cause both jaws to move laterally permitting the placement of an object in a corner. As shown in Figure 5, the jaws 124 and 126 may be brought together until jaw-anchoring flanges 120 and 122 abut each other, so as to permit very small objects to be grasped by the jaws.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having fully described the invention, I claim:

1. A load clamp for a lift truck and the like including a frame assembly having a pair of vertically spaced stationary horizontal guides, a cylinder fixedly joined to said frame assembly, disposed in each of said stationary guides, a primary slide member guidably supported in each of said guides, a piston rod from each cylinder connected to its adjoining primary slide member for moving said primary slide member between extended and retracted positions, a jaw-carrying secondary slide member guidably supported by each primary slide member, and pulleyand-chain means for amplifying the relative amount of movement of each of said secondary slide members in relation to its primary slide member on each of said primary slide members comprising a chain carried between pulleys on the primary slide member, with a link on one span of the chain fixedly connected to said frame assembly and a link on the other span of the chain connected to the secondary slide member.

2. A load clamp for a lift truck and the like comprising a back plate, a pair of vertically spaced horizontal stationary guides fixedly joined to said back plate, a reciprocally movable primary slider guidably supported in each of said guides, a cylinder disposed in each of said guides and fixedly joined to said back plate, said cylinder not obstructing the horizontal reciprocal movement of said primary slider, a piston rod in each cylinder connected to its associated primary slider, a generally U-shaped secondary slider reciprocally mounted in each primary slider, with the base of the U disposed away from the back plate so as to straddle the cylinder disposed in the guide for its primary slider, and with the legs of the U traveling in the primary slider, pulley-and-chain means for amplifying the relative amount of said second slider in relation to its associated primary slider comprising a pair of pulleys mounted on one side of said primary slider, a chain spanning said pulleys, one link on one span of said chain fixedly connected to the back plate, and one link on the opposite span connected to the secondary slider, and a load-grasping jaw fixedly joined to each of said secondary sliders.

3. A load clamp for a lift truck and the like compriserally U-shaped secondary slider reciprocally mountedv in each primary slider, with the base of the U disposed away from the back plate so as to straddle the cylinder disposed in the guide for its primary slider, and with the legs of the U traveling in the primary slider, pulley-andchain means for amplifying the relative amount of movement of said second slider in relation to its associated primary slider comprising a pair of pulleys mounted on one side of said primary slider, a chain spanning said pulleys, one link on one span of said chain fixedly connected to the back plate, and one link on the opposite span connected to the secondary slider, and a loadgrasping jaw fixedly joined to each of said secondary sliders, said jaw having fiexible jaw pads.

4. In a lift truck, a lift frame, a lift carriage carried by said frame, said lift carriage including a back plate, a pair of vertically spaced horizontal stationary guides fixedly joined to said back plate, a reciprocally movable primary slider guidably supported in each of said guides, a cylinder disposed in each of said guides and fixedly joined to said back plate, said cylinder not obstructing the horizontal reciprocal movement of said primary slider, a piston rod in each cylinder connected to its associated primary slider, a generally U-shaped secondary slider reciprocally mounted in each primary slider, with the base of the U disposed away from the back plate so as to straddle the cylinder disposed in the guide for its primary slider, and with the legs of the U traveling in the primary slider, pulley-and-chain means for am plifying the relative amount of movement of said second slider in relation to its associated primary slider comprising a pair of pulleys mounted on one side of said primary slider, a chain spanning said pulleys, one link on one span of said chain fixedly connected to the back plate, and one link on the opposite span connected to the secondary slider, and a load-grasping jaw fixedly joined to each of said secondary sliders.

References Cited in the file of this patent UNITED STATES PATENTS 1,579,975 Tunison Apr. 6, 1926 2,352,129 Shonnard June 20, 1944 2,461,877 Brereton Feb. 15, 1949 2,625,424 Hyman Jan. 13, 1953 2,663,443 Schenkelberger Dec. 22, 1953 2,671,571 Gerhardt Mar. 9, 1954 2,699,878 Avery Ian. 18, 1955 2,726,780 Rodman Dec. 13, 1955 

